It is known to have a rear window opening in a truck cab including a central opening defined between a pair of stationary window panes and to provide one or more laterally slidable window panes therebetween. The slidable window panes each typically are movable between a closed position closing the central opening and an open position opening the central opening. The slidable window panes each partially overlie one of the stationary window panes in the open position.
The slidable window panes may be moved between the open and closed positions either manually or by use a of a power drive mechanism. For example, it is known to have a reversible motor which drives a rack and pinion, cable, slotted tape, or some combination thereof for moving the slidable window panes between the open and closed positions. However, the power drive mechanisms of the prior art have numerous shortcomings which make the power window assembly cumbersome and expensive.
For example, the power drive mechanisms of the prior art are typically positioned within or integrally connected in some manner to a frame assembly which is mounted to the vehicle body and holds the window panes. Thus, the power drive mechanism must be purchased as a cumbersome and expensive power window assembly which includes the window panes and a specially modified frame integrally assembled with the power drive mechanism. In operation, these prior art power window assemblies typically push the window in one direction and pull the window in the other direction, thus limiting the smoothness of the window movement. In addition, extra parts are required such as a track or sheath in which the flexible cable or tape rides to prevent buckling during pushing movement of the window panes between the open and closed positions.
The prior art power window assemblies also have the shortcoming of having a rigid nonadjustable connection to the slidable window panes, thus being highly sensitive to dimensional variations. To avoid this shortcoming, the prior art power drive mechanism is integrally connected to the window assembly and sold as a replacement unit for the manually movable window assembly already provided with the vehicle. However, when the power window assembly is sold as a replacement unit to alleviate dimensional concerns between the power drive mechanism and the window assembly, then other dimensional fit concerns occur between the replacement unit and the truck body. Thus, prior art power window assemblies also have the disadvantage of high repair and replacement costs. Additionally, prior art power window assemblies have many components which are complex to assemble, require numerous fasteners, and are not easily adaptable to fit different size windows or to accommodate either one or two sliding window panes. Prior art assemblies also have the shortcoming of requiring different designs for the various curvatures or channel sweeps of the vehicle body surrounding the windows.